We study two-loop electroweak virtual corrections to four-fermion scattering mediated by a $W^{\pm}$ or $Z$ boson within the pole approximation.
The latter organises higher-order corrections into two separately gauge-invariant categories, factorisable and non-factorisable, respectively.
While the factorisable corrections can be obtained from the corresponding vector-boson form factors, the non-factorisable effects arise from soft-photon exchange between the production and decay stages.
In this report, we present the results for the two-loop non-factorisable corrections, showing that, after decoupling the heavy degrees of freedom, they reduce to an iteration of the one-loop result supplemented by a novel light-fermion contribution.